PATHOGENIC BACTERIA. 327 



those of the spirillum of cholera, and the margin is almost abso- 

 lutely smooth and circular. As the colonies become older 

 they assume a more irregular and lobulated appearance, but 

 are still more finely granular than the colonies of the cholera 

 spirillum. Gelatin is very slowly hquefied. Its growth on the 

 other culture-media is not remarkable. It forms indol in pep- 

 tone solution, and it increases in the upper layers of the fluid. 

 When guinea-pigs are inoculated in the peritoneal cavity, death 



Fig. 100. — Spirillum of Relapsing Fever in the Blood. Sketched 

 FROM A Stained Specimen. 



occurs in one to two days. This organism was discovered in 

 the water-supply of Berhn. 



Other spirilla have been isolated from water by Giinther 

 (Vibrio aquatihs in Spree water) ; by Dunbar from the Elbe 

 River; by RusseU from the Gulf of Naples; by Heider f rom the 

 water of the Danube Canal; and in America, by Abbott, from 

 the water of the Schuylkill (Vibrio Schuylkiliensis) ; and many 

 others have been described to which the limits of this work 

 will not permit of further allusion. 



